On-line hemodiafiltration. Gold standard or top therapy?

In summary, on-line HDF is an extracorporeal blood purification therapy with increased convective removal of uremic toxins as compared to the most frequently used low- or high-flux HD therapy. The clinical advantages of on-line HDF have shown to be dose dependent, which makes on-line HDF superior to other therapies with less convective solute removal. Among the therapies with high convective solute removal, i.e. on-line HDF, on-line HF and double high-flux dialysis, it is difficult to finally decide on the best therapy, as direct comparisons of these therapies are not performed. Theoretical considerations like the relative to on-line HDF lower achievable Kt/Vurea with on-line HF, allow to state that on-line HDF is the top therapy now available for patients with ESRD. A gold standard may be defined as something with which everything else is compared if one tries to establish it in the respective field. In order to declare on-line HDF as the gold standard in renal replacement therapy, we need more direct comparisons of on-line HDF with other therapies, including mortality as an outcome parameter. However, based on our current knowledge, it does not seem to be too speculative that high-quality clinical studies will establish on-line HDF in the next years as the new gold standard in renal replacement therapy.